President Donald Trump’s proposed border wall has drawn the interest of hundreds of companies, but the larger, more experienced firms might not be on board. The deadline to submit proposals for the wall was Tuesday at 4 p.m. ET, and many of the biggest construction and engineering companies are steering clear of bidding for the project altogether. Several companies who otherwise possess the resources and experience to manage and deliver such a large and complex project are staying away from it largely due to concerns about political backlash, according to Dave Raymond, President and CEO of the American Council on Engineering Companies. He told CNN, “in my lifetime, I can’t think of a similar experience.” One senior official from a construction firm told CNN via email that “there are many hurdles associated with the wall, ranging from political ones to financing to the very real human aspect. There are also concerns about how working on the wall would affect a construction company’s ability to work in other countries, given that the Trump plan has received a great deal of international criticism.” As of Tuesday afternoon, the three largest recipients of federal government contracts, as ranked by the Engineering News-Record’s most recent Top 400 Contractors list – Bechtel, Fluor Corp., and Turner Corp. (no relation to CNN parent company Turner Broadcasting) – are not listed as interested vendors for the US Customs and Border Protection’s two requests for proposals (RFPs) that closed Tuesday at 4 p.m. When asked about their respective plans, Bechtel previously noted that it has not expressed interest in the wall, Fluor told CNN it “does not publicly discuss whether or not the company is pursuing or will pursue specific contract opportunities,” and Turner told CNN it would not be pursuing the project, saying they are focused on other projects such as building stadiums and airports. In fact, only three of the top 20 ranked contractors were listed as interested vendors on those RFPs. More than 200 companies have expressed interest in each RFP. Some firms are worried about potentially losing future business with the nation’s largest cities and states, according to Raymond, whose organization represents more than 5,000 engineering firms throughout the country. State lawmakers in both California and New York have introduced bills that would effectively blacklist any company involved in building the border wall from future state business. Neither of the bills has passed into law, but the possibility alone has turned off many potential bidders. “The state initiatives have really had a chilling effect on companies which otherwise would have sought involvement on these projects,” Raymond told CNN. “While these companies, generally speaking, think these state initiatives are grossly unfair, they are not going to presumably risk their standing in those states by getting involved in these projects.” Raymond said companies could stand to lose hundreds of millions of dollars in potential business with these states should the laws pass. Last week the president of Mexican cement giant Cemex said, “I want to be very clear on this topic: Cemex will not participate in the construction of the wall.” Cemex previously said it would provide building materials for the wall to clients if asked. Their recent clarification came in the wake of Mexican Foreign Minister Luis Videgaray telling Mexican companies to “examine their conscience” when considering bidding for the wall, a possible sign of the political pressure some of these companies are weighing. First on CNN: Border wall ask: $1 billion for 62 miles With some of the largest players likely sitting out the bidding process, the work may end up being awarded to smaller firms with fewer resources, although that process is still months away. One industry insider who works for a larger firm that is not competing for the wall told CNN that he was concerned that the firms currently listed as interested vendors may not be capable of completing the project. These small-to-medium sized firms could have issues with bonding and hiring workers to build the wall, the source said. This insider also worries about these small firms’ ability to scale up and manage a project of this size. CNN has reached out to US Customs and Border Protection for comment on this concern, but has yet to hear back. When presented with this line of thinking, Raymond disagreed that the smaller companies would not be able to handle the project, and pointed out that the process is still in its very early stages. “The biggest problem with this project is the political side, not the engineering side,” Raymond said, referring specifically to the state initiatives aimed at punishing companies that work on the wall. Another concern facing any firm that works on the wall will be the complications that result from eminent domain lawsuits. The Trump administration will have to seize private property from thousands of Americans in order to complete the wall, a move that “is expected to prompt years of legal battles, cost tens of millions in taxpayer dollars and delay construction,” according to a new CNN investigation of lawsuits filed over the 2006 Secure Fencing Act – the last time the government took private land to build a border barrier.